On-board diagnostic (OBD) tests analyze vehicle operations and may identify problems with vehicle components. OBD tests may be delayed and/or performed sparingly, however, because performing the OBD tests often depends on satisfying prerequisite (sometimes referred to as entry) conditions before and/or during a the test. Examples of OBD tests include an evaporative emissions control (EVAP) test, an exhaust gas recirculation (EGR) test, an oxygen sensor test, a heated catalyst test, to name a few. Examples of entry conditions include fuel volume between 15% and 85% of capacity, ambient temperature from 40° Fahrenheit to 95° Fahrenheit, altitude less than 8500 feet, vehicle speed greater than 25 miles per hour, etc.